import jdk.internal.org.objectweb.asm.Handle;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: Administrator
 * Date: 2024-10-02
 * Time: 16:18
 */
public class SingleLinkedList {
    static class ListNode {
        public int val;
        public ListNode next;

        public ListNode(int val) {
            this.val = val;
        }
    }

    public ListNode head;
    private int usedSize;

    public void createList() {
        ListNode node1 = new ListNode(12);
        this.usedSize++;
        ListNode node2 = new ListNode(23);
        this.usedSize++;
        ListNode node3 = new ListNode(34);
        this.usedSize++;
        ListNode node4 = new ListNode(45);
        this.usedSize++;
        ListNode node5 = new ListNode(56);
        this.usedSize++;

        node1.next = node2;
        node2.next = node3;
        node3.next = node4;
        node4.next = node5;
        this.head = node1;
    }

    public void display() {
        ListNode cru = head;
        while (cru != null) {
            System.out.print(cru.val + " ");
            cru = cru.next;
        }
        System.out.println();
    }

    //头插法
    public void addFirst(int data) {
        ListNode node = new ListNode(data);
        node.next = head;
        head = node;
        this.usedSize++;
    }

    //尾插法
    public void addLast(int data) {
        ListNode node =new ListNode(data);
        ListNode cur = head;

        if (cur == null){
            head = node;
            return;
        }
        while (cur.next != null){
            cur = cur.next;
        }
            cur.next = node;
            this.usedSize++;
    }

    public int size(){
//        int count = 0;
//        ListNode cur = head;
//        while (cur != null){
//            count++;
//            cur = cur.next;
//        }
//        return count;
        return this.usedSize;
    }

    //查找是否包含关键字key是否在单链表当中
    public boolean contains(int key) {
        ListNode cur = head;
        while (cur != null){
            if(cur.val == key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    public void addIndex(int index,int data){
        if(index < 0 || index > size()){
            System.out.println("index 不合法");
            return;
        }
        if(index == 0){
            addFirst(data);
            return;
        }
        if(index == size()){
            addLast(data);
            return;
        }
        ListNode cur = findIndexSubOne(index);
        ListNode node = new ListNode(data);
        node.next = cur.next;
        cur.next = node;
    }

    private ListNode findIndexSubOne(int index){
        ListNode cur = head;
        while (index - 1 != 0){
            cur = cur.next;
            index--;
        }
        return cur;
    }
    //删除第一次出现关键字为key的节点
    public void remove(int key) {
        if(head == null){
            return;
        }
        if(head.val == key){
            head =head.next;
            return;
        }

        ListNode cur =  searchPrev(key);
        if(cur == null){
            System.out.println("没有你要删除的数字。");
            return;
        }
        ListNode del = cur.next;
        cur.next = del.next;
    }

    private ListNode searchPrev(int key){
        ListNode cur = head;
        while(cur.next != null){
            if(cur.next.val == key){
                return cur;
            }
            cur = cur.next;
        }
        return null;
    }

    public void removeAllKey(int key){
        if (head == null){
            return;
        }
        ListNode prev = head;
        ListNode cur = prev.next;
        while (cur != null){
            if(cur.val == key){
                cur = cur.next;
            }else {
                prev = cur;
                cur = cur.next;
            }
        }
        if(head.val == key){
            head = head.next;
        }
    }
    public void clean(){
        this.head = null;
    }
}


